P0340 Misfire Issue (1 Viewer)

[tjones8]

Couple days ago my 80 started to misfire violently at low rpm/speed from a stop. Code is for the cam position sensor (the distributor basically)

Replaced:

Distributor
Plugs
Wires
Crank position sensor
Throttle position sensor

Also did:

Seafoam through the intake manifold
B12 Chemtool in the tank

Next on the list is a fuel filter

Upon completing the distributor swap, I checked timing with a light, adjusted to 3 degrees with the TPS at 9. When I came back from my drive the timing had set itself back to 0

Next I advanced timing to 6, and upon coming back again it had advanced itself to about 10 degrees.

I don’t believe bad gas is the culprit, I have a tank of Shell 91 in right now

I’m running out of ideas here, only other thing I can think of besides the fuel filter is would be an IAC valve, which is unlikely, but I’ve read of guys that had this issue or similar and that fixed it

I’m just getting tired of throwing money at the thing

any suggestions?

 

[tjones8]

I’ll add as well, the distributor adjustment screw is as tight as I can get it

 

[tjones8]

******** EDIT: Thought maybe it self advancing its timing after setting it in DTC mode was the culprit. Set timing in DTC to 0 to (possibly) compensate for it advancing itself, pulled the jumpers, still at zero, took it for a drive (still misfires in first gear) pulled it back in and it’s still dead nuts at 0 degrees.

 

[tjones8]

Bump

anyone have any ideas?

 

[BILT4ME]

I missed by this thread earlier.

What year is your truck?

Did you use the paperclip to bypass to reset the timing?

You must follow the retaining procedure for it to stick.

Do you have an FSM?

Have you checked your intake hose for cracks?

Check your wiring harness by the egr for burned wires.

 

[tjones8]

I missed by this thread earlier.

What year is your truck?

Did you use the paperclip to bypass to reset the timing?

You must follow the retaining procedure for it to stick.

Do you have an FSM?

Have you checked your intake hose for cracks?

Check your wiring harness by the egr for burned wires.

Wow can’t believe I typed all that and didn’t include that. Truck is a 95.

yes I grounded TE1 and E1, but my CEL will not blink, but it seems to work because I had advanced the timing to 6, then went back to check it again and it was sticking at *almost*3, it was right at 4 very steadily idling great.

I do not have a FSM unfortunately.

the silicone hose is brand new, but I noticed last night my hose seems to be separating a bit right where the steel part bolts to the MAF housing.

In my reading last night I did see mentions of that harness next to the EGR, I’m going to take a look at that as well when time permits

 

[tjones8]

I will add the intense fuel cut/misfire/bucking is ONLY in first gear. All other gears it runs awesome. Especially when it adjusted it self to about 10 degrees of timing but obviously, that’s not a longevitive option

 

[BILT4ME]

Get a free FSM here:

For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.

[new edit] go here instead - Resources - https://forum.ih8mud.com/resources/ It's an end of an era my friends. As of tomorrow I'm being forced by my isp provider to shut this down. I just cannot take the chance on losing my hosting for my e-mail and other things. I'm working on finding a...

forum.ih8mud.com

 

[tjones8]

Get a free FSM here:

For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.

[new edit] go here instead - Resources - https://forum.ih8mud.com/resources/ It's an end of an era my friends. As of tomorrow I'm being forced by my isp provider to shut this down. I just cannot take the chance on losing my hosting for my e-mail and other things. I'm working on finding a...

forum.ih8mud.com

Interesting, no 1995 Manual

 

[BILT4ME]

Interesting, no 1995 Manual

95 is the same as 96.

What's your build date from the VIN tag?

 

[BILT4ME]

My 96 has a build date of 8/95.

 

[tjones8]

I’ll have to look. Truck is sitting at the house